An integrated EGR system and engine

Abstract

This utility model relates to the field of engine control technology, specifically to a built-in EGR system and engine, including an intake manifold and an exhaust manifold disposed within the cylinder head. The intake manifold and the exhaust manifold are connected, and a one-way valve is provided between them, allowing exhaust gas to enter the intake manifold from the exhaust manifold. During the exhaust phase, exhaust gas is temporarily stored in the intake manifold via the one-way valve using a pressure difference, and then drawn back into the cylinder along with fresh air during the intake phase. This reduces combustion temperature by diluting oxygen with exhaust gas and increasing the specific heat capacity of the air-fuel mixture, thereby suppressing NOx formation at the source and enabling engines without aftertreatment to meet emission regulations such as Stage 3A. Furthermore, this system requires no external control or additional components, making it simple in structure and low in cost, suitable for underdeveloped regions. Moreover, by reducing NOx, it allows for more efficient fuel economy calibration and reduces pumping losses, ultimately significantly improving fuel economy.

Description

Technical Field

[0001] This utility model relates to the field of engine control technology, specifically to a built-in EGR system and engine. Background Technology

[0002] The statements in this section are merely background information related to this utility model and do not necessarily constitute prior art.

[0003] EGR (Exhaust Gas Recirculation) is a technology that introduces a portion of the exhaust gases produced after engine combustion back into the intake manifold, mixes with fresh air, and then re-enters the cylinders for combustion. This technology can lower the combustion temperature, thereby reducing the emission of harmful nitrogen oxides (NOx).

[0004] In the EGR system, the high-temperature exhaust gas is cooled down and then the flow rate of the recirculated exhaust gas is controlled by the EGR valve, which in turn opens and closes in response to the commands of the engine electronic control unit (ECU).

[0005] Most EGR systems are externally mounted, using external pipes and valves to guide exhaust gas from the exhaust manifold back to the intake manifold.

[0006] The built-in EGR has no external pipes, valves or coolers. It achieves the retention of exhaust gas by controlling the exhaust valve to close early or the intake valve to open late at specific times through the engine's valve timing system.

[0007] Built-in EGRs are less expensive than external EGRs because they do not require external piping and coolers. However, the EGR rate (the amount of exhaust gas recirculated) that a built-in EGR can achieve is usually lower than that of an external EGR, making it difficult to meet stringent emission regulations.

[0008] When engines operate in less developed regions and countries, emission standards are relatively less stringent (e.g., lower than non-IV or China VI standards), and due to cost sensitivity, they often employ built-in EGR systems. However, existing built-in EGR systems, by actively trapping some exhaust gases in the cylinders or re-drawing some exhaust gases back into the cylinders, are prone to improper valve timing. This can interfere with the normal intake and exhaust process, potentially affecting engine power and torque output, resulting in poor fuel economy. Utility Model Content

[0009] In order to solve the technical problems existing in the background art, the present invention provides a built-in EGR system and engine, which connects the intake manifold and the exhaust manifold, and sets a one-way valve in the connected channel. The one-way valve introduces the exhaust gas into the intake manifold, and at the same time prevents the gas in the intake manifold from flowing back into the exhaust manifold.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of this utility model provides a built-in EGR system, including an intake manifold and an exhaust manifold disposed in the cylinder head, the intake manifold and the exhaust manifold being connected, and a one-way valve being provided between the intake manifold and the exhaust manifold, the one-way valve allowing exhaust gas to enter the intake manifold from the exhaust manifold.

[0011] Furthermore, the intake duct is connected to an intake valve, and the exhaust duct is connected to an exhaust valve.

[0012] Furthermore, the intake and exhaust valves are located inside the cylinder.

[0013] Furthermore, an intake pressure regulating chamber is provided inside the intake duct.

[0014] Furthermore, the one-way valve includes a valve body with an exhaust gas inlet and an exhaust gas outlet. A valve core is located inside the valve body and is connected to the valve body via an elastic element. The elastic element pushes the valve core to press against the valve body.

[0015] Furthermore, the one-way valve includes a valve body, which has a waste gas inlet and a waste gas outlet. The valve body has a first flow channel communicating with the waste gas inlet, a third flow channel communicating with the waste gas outlet, and a second flow channel communicating with the first flow channel and the third flow channel.

[0016] Furthermore, the second flow channel is arc-shaped.

[0017] Furthermore, the first flow channel is connected to the exhaust gas inlet at its head, the middle of the first flow channel is connected to the head of the second flow channel, and the end of the first flow channel is connected to the middle of the third flow channel.

[0018] Furthermore, the end of the second flow channel is connected to the beginning of the third flow channel, and the end of the third flow channel is connected to the exhaust gas outlet.

[0019] A second aspect of this invention provides an engine having the aforementioned built-in EGR system.

[0020] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects: By utilizing pressure differential during the exhaust phase to temporarily store exhaust gases through a one-way valve into the intake manifold, and then drawing them back into the cylinder along with fresh air during the intake phase, this system lowers combustion temperature by diluting oxygen with exhaust gases and increasing the specific heat capacity of the air-fuel mixture. This suppresses NOx formation at its source, enabling engines without aftertreatment to meet emission regulations such as Stage 3A. Furthermore, this system requires no external controls or additional components, making it simple in structure and low in cost, suitable for underdeveloped regions. Moreover, by reducing NOx, it allows for more efficient fuel economy calibrations and reduces pumping losses, ultimately significantly improving fuel economy. Attached Figure Description

[0021] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0022] Figure 1 This is a schematic diagram of the built-in EGR system structure provided by this utility model; Figure 2 This is a schematic diagram of the one-way valve structure provided by this utility model; Figure 3 This is a schematic diagram of the Tesla valve structure provided by this utility model; In the diagram: 1. Cylinder, 2. Cylinder head, 3. Intake manifold, 4. Exhaust manifold, 5. Intake valve, 6. Exhaust valve, 7. One-way valve, 8. First flow channel, 9. Second flow channel, 10. Third flow channel. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] The following is an explanation of some of the technical terms used in this solution: One-way valve: A valve used to control the unidirectional flow of fluid; Tesla valve: When flowing in the forward direction, the fluid can pass through smoothly with little energy loss; however, when flowing in the reverse direction, it will cause eddies, flow separation and turbulence, resulting in the dissipation of kinetic energy, forming significant back pressure and hindering the flow. Built-in EGR system: A system that reduces nitrogen oxide emissions by reintroducing some exhaust gas into the engine combustion chamber without the need for external pipes and external cooling devices.

[0026] As described in the background section, existing built-in EGR systems essentially work by precisely controlling the timing of valve opening and closing to actively retain a portion of the exhaust gas in the cylinder, or to re-draw some of the exhaust gas back into the cylinder. This is completely different from the physical logic of external EGR systems, which "draw exhaust gas back from external pipes." It is a more sophisticated valve management strategy that relies more heavily on "software and control systems."

[0027] Under normal circumstances, during the exhaust stroke, the piston moves upward, pushing the exhaust gases out of the cylinder. When the piston reaches top dead center, the exhaust valve closes, and all the exhaust gases that can be expelled have entered the exhaust pipe.

[0028] The built-in EGR system closes the exhaust valve early, before the piston reaches top dead center. This traps some exhaust gases in the combustion chamber, preventing them from escaping. Then, the intake valve opens, initiating the intake stroke, and fresh air mixes with the trapped exhaust gases, achieving exhaust gas recirculation.

[0029] Because built-in EGR systems lack an independent cooling system, the temperature of the trapped exhaust gas remains relatively high, resulting in limited heat absorption capacity and difficulty in controlling the temperature of the cylinder combustion chamber. Furthermore, the control method of built-in EGRs is relatively "crude." Over-adjusting valve timing can interfere with the normal intake and exhaust process, leading to negative effects such as reduced engine torque and unstable combustion, resulting in poor fuel economy. Therefore, it can only be used in some less developed regions with relatively low emission requirements.

[0030] The built-in EGR system proposed in this solution differs from the traditional built-in EGR system which uses "adjusting valve timing". Instead, it connects the intake and exhaust manifolds and installs a one-way valve in the connected passage, allowing exhaust gas to enter the intake manifold from the exhaust manifold. This meets emission requirements without adjusting valve timing and improves the fuel economy of the diesel engine.

[0031] Example 1: like Figure 1 As shown, a built-in EGR system includes a cylinder 1 and a cylinder head 2. The cylinder head 2 is provided with an intake passage 3 and an exhaust passage 4. An intake valve 5 is provided at the end of the intake passage 3, and an exhaust valve 6 is provided at the beginning of the exhaust passage 4. The intake valve 5 and the exhaust valve 6 are located inside the cylinder 1. A one-way valve 7 is provided between the intake duct 3 and the exhaust duct 4. The one-way valve 7 allows exhaust gas to enter the intake duct 3 from the exhaust duct 4.

[0032] The first end of the air intake duct 3 is connected to the air intake pipe, and the last end of the exhaust duct 4 is connected to the exhaust pipe.

[0033] The intake duct 3 is equipped with an intake pressure stabilizing chamber.

[0034] During the exhaust phase (forward flow): When exhaust valve 6 opens, high-pressure exhaust gas rushes into exhaust duct 4. A portion of the exhaust gas passes through one-way valve 7, which is designed with "forward low flow resistance," allowing the exhaust gas to flow relatively smoothly into intake duct 3 and intake pressure regulating chamber, filling them completely. Intake phase (exhaust gas recovery): When intake valve 5 opens, fresh air is drawn in. At this time, the exhaust gas stored in intake manifold 3 and pressure regulating chamber is "drawn back" into the cylinder along with the fresh air.

[0035] The introduced exhaust gases (mainly CO2 and N2) increase the specific heat capacity of the air-fuel mixture and dilute the oxygen concentration, thereby effectively reducing the combustion flame temperature and suppressing the formation of nitrogen oxides (NOx) at its source. This allows the engine to meet regulations such as Stage 3A and IMO Tier II without an aftertreatment system.

[0036] Compared to traditional calibration strategies that sacrifice injection timing to meet emission standards (leading to poorer fuel economy), this system introduces exhaust gases into the intake manifold instead of trapping them in the cylinders using a traditional built-in EGR. This reduces NOx, allowing the engine to employ more efficient combustion calibration and thus improving fuel economy. Furthermore, the system eliminates the need for an additional cooler, drive valves, and long piping, resulting in relatively lower pumping losses and further contributing to fuel efficiency.

[0037] During operation, the EGR system of this solution relies entirely on the intake and exhaust pressure fluctuations and valve action of the engine itself, without the need for external forced control (such as EGR valve), cooling or drive. It is part of the engine's own working process and can address cost-sensitive issues in underdeveloped regions.

[0038] The one-way valve 7 is not limited to a specific structural form; for example, it can adopt a design such as... Figure 2 The one-way valve shown includes a valve body with an exhaust gas inlet and an exhaust gas outlet. A valve core is located inside the valve body and is connected to the valve body via an elastic element. The elastic element deforms under a pre-applied preload, pushing the valve core to press against the valve body, thereby cutting off the exhaust gas inlet and outlet. When the exhaust valve 6 is opened, the exhaust gas in the exhaust passage 4 uses its own pressure to push the valve core open, sending a portion of the exhaust gas into the intake passage 3 along the passage where the one-way valve 7 is located. When the pressure in the exhaust passage 4 drops below the preload of the elastic element, the valve core closes again under the push of the elastic element.

[0039] By selecting the valve core structure and the performance of the elastic element, the flow resistance of the one-way valve is lower than the set value during the exhaust stroke, when exhaust gas flows from the exhaust port to the intake port (forward flow). During the intake stroke, when there is negative pressure in the intake port and the exhaust port pressure has also decreased, it can reliably prevent airflow from flowing back from the intake port to the exhaust port. Other methods include Figure 3 The Tesla valve shown includes a valve body with an exhaust gas inlet and an exhaust gas outlet. The valve body has a first flow channel 8 connected to the exhaust gas inlet, a third flow channel 9 connected to the exhaust gas outlet, and a second flow channel 9 connecting the first flow channel 8 and the third flow channel 9. The second flow channel 9 is arc-shaped. The first flow channel 8 is connected to the exhaust gas inlet at its head, the middle of the first flow channel 8 is connected to the head of the second flow channel 9, and the end of the first flow channel 8 is connected to the middle of the third flow channel 10. The end of the second flow channel 9 is connected to the beginning of the third flow channel 10, and the end of the third flow channel 10 is connected to the exhaust gas outlet.

[0040] Tesla valves do not have the moving parts of traditional check valves. Instead, through the arrangement of the flow channels inside the valve body, the resistance to fluid flow in one direction is very small, while the resistance in the opposite direction is extremely large, thus achieving the function of a check valve (one-way valve) without moving parts.

[0041] When the exhaust gas flows from the exhaust gas inlet to the exhaust gas outlet, it flows in the forward direction. At this time, the exhaust gas flows along the first flow channel 8 and the third flow channel 10. The exhaust gas in the bifurcation loop formed by the first flow channel 8 and the third flow channel 10 is generally in the same direction as the fluid in the main channel. (Angle less than 90°) and less interference.

[0042] When flowing in reverse: the exhaust gas forks into two paths at the end of the first flow channel 8 and the middle of the third flow channel 10. One path flows along the first flow channel 8 towards the exhaust gas inlet, while the other path passes through the arc-shaped second flow channel 9 and meets the exhaust gas from the first flow channel 8 at the beginning of the second flow channel 9. Because... When the angle is greater than 90°, the exhaust gases in the two loops collide with each other, consuming most of the kinetic energy, thus creating flow resistance.

[0043] The above structure allows the main flow and the branch flow to collide only once. Although a single collision consumes some of the fluid's kinetic energy (manifested as pressure loss), the effect is temporary and limited. Therefore, this structure forms a valve unit. In practical applications, to prevent fresh air from flowing back into the exhaust duct, multiple valve units are used in series to achieve the required flow resistance.

[0044] Example 2: An engine having the aforementioned built-in EGR system, the EGR system including an intake manifold and an exhaust manifold disposed within a cylinder head, the intake manifold and the exhaust manifold being connected, and a one-way valve being provided between the intake manifold and the exhaust manifold, the one-way valve allowing exhaust gas to enter the intake manifold from the exhaust manifold.

[0045] As a further embodiment, the intake duct is connected to an intake valve, and the exhaust duct is connected to an exhaust valve.

[0046] As a further implementation, the intake valve and exhaust valve are located inside the cylinder.

[0047] As a further implementation, an intake pressure regulating chamber is provided in the intake duct.

[0048] As a further embodiment, the one-way valve includes a valve body with a waste gas inlet and a waste gas outlet. A valve core is provided inside the valve body, and the valve core is connected to the valve body through an elastic element. The elastic element pushes the valve core to press against the valve body.

[0049] As a further embodiment, the one-way valve includes a valve body with a waste gas inlet and a waste gas outlet. The valve body has a first flow channel communicating with the waste gas inlet, a third flow channel communicating with the waste gas outlet, and a second flow channel communicating with the first flow channel and the third flow channel.

[0050] As a further implementation, the second flow channel is arc-shaped.

[0051] As a further embodiment, the first end of the first flow channel is connected to the exhaust gas inlet, the middle part of the first flow channel is connected to the first end of the second flow channel, and the end of the first flow channel is connected to the middle part of the third flow channel.

[0052] As a further implementation, the end of the second flow channel is connected to the beginning of the third flow channel, and the end of the third flow channel is connected to the exhaust gas outlet.

[0053] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A built-in EGR system, characterized in that, It includes an intake manifold and an exhaust manifold disposed within the cylinder head, the intake manifold and the exhaust manifold being connected, and a one-way valve being provided between the intake manifold and the exhaust manifold, the one-way valve allowing exhaust gas to enter the intake manifold from the exhaust manifold.

2. The built-in EGR system as described in claim 1, characterized in that, The air intake duct is connected to an air intake valve, and the exhaust duct is connected to an exhaust valve.

3. The built-in EGR system as described in claim 2, characterized in that, The intake valve and the exhaust valve are located inside the cylinder.

4. A built-in EGR system as described in claim 1, characterized in that, The air intake duct is equipped with an air intake pressure stabilizing chamber.

5. A built-in EGR system as described in claim 1, characterized in that, The one-way valve includes a valve body with an exhaust gas inlet and an exhaust gas outlet. A valve core is provided inside the valve body and is connected to the valve body by an elastic element. The elastic element pushes the valve core to press against the valve body.

6. A built-in EGR system as described in claim 1, characterized in that, The one-way valve includes a valve body, which has a waste gas inlet and a waste gas outlet. The valve body has a first flow channel communicating with the waste gas inlet, a third flow channel communicating with the waste gas outlet, and a second flow channel communicating with the first flow channel and the third flow channel.

7. A built-in EGR system as described in claim 6, characterized in that, The second flow channel is arc-shaped.

8. A built-in EGR system as described in claim 6, characterized in that, The first flow channel is connected at its head to the exhaust gas inlet, the middle of the first flow channel is connected to the head of the second flow channel, and the end of the first flow channel is connected to the middle of the third flow channel.

9. A built-in EGR system as described in claim 6, characterized in that, The end of the second flow channel is connected to the beginning of the third flow channel, and the end of the third flow channel is connected to the exhaust gas outlet.

10. An engine, characterized in that, It has a built-in EGR system as described in any one of claims 1-9.

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